there's nothing between the 2 electrodes, that's just a smudge on the glass tubing.. it reminds me of one of them high voltage flashes from a camera, no part number, found it in a box of electronics that were going to be thrown out..

Spark gaps also appear in assorted telecommunications equipment; the kind that connect to long wires strung through the air... They're apparently required due to regulatory issues; I don't know if they'd do any good in the event of a nearby lightning strike.